Drying cylinder



March 14, 1967 G. ovER'roN DRYING CYLINDER Original Filed June l5, 1964 Hwa/v IOR @/en @Verf/7 A TTOR NE YS United States Patent 6 claims. (ci. 3ft- 124) rThis application is a continuation of application Serial No. 375,035, filed on June 15, 1964, now abandoned.

This invention relates to apparatus for increasing the heat flow through the shell of a drying cylinder or drum and more specifically relates to the provision of steam jets on the inside of a drying cylinder or drum for simultaneously heating the shell While maintaining the condensate or carryover water at the bottom of the shell.

In accordance with this invention a dryer drum composed of a cylindrical shell and end heads is heated by introducing steam or other heating fluid into the drum from a series of jets spaced along the length of the drum at the 3 and 9 oclock positions of the shell and in close proximity to the shell. Steam or other heating fluid is also introduced into the central zone of the drum. The steam jets impinge downwardly on the shell and drive condensate water to the bottom of the drum where it is removed by a syphon tube or the like removal device. The heating fluid introduced `into the central zone of the drum causes and maintains a pressure in the drum somewhat less than the pressure maintained at the steam jets and augments the heating effect of the steam jets. The pressures of the jet feed system and the central zone feed system can be controlled to meet drying conditions of different products. For example the lowering of the central zone feed pressure and the increasing of the pressure in the small jets creates a greater impact force against the cylinder wall or shell which is desirable for destroying any water lm that might tend to build up in the shell but may also result in development `of hot spots at the jet areas. Drum temperatures can thus be regulated around the periphery of the shell fby regulation of the steam pressure feed to iboth systems.

It is then an object of this invention to provide apparatus for heating dryer cylinders or drums which also increases the heat ow through the shell of the drying cylinder or drum.

A further object of this invention is to provide a steam jet heating system for drying cylinders and drums which prevents condensate water from forming a film around the interior of the shell.

Another object of the invention is to provide a steam jet heating system for drying dmms which maintains the carryover condensate water at the bottom of the drum shell.

A still further object of the invention is to provide a heating system for drying drums and cylinders which includes a central zone feed and a peripheral zone feed with the peripheral zone feed having an added function of maintaining condensate water at the bottom of the drum.

Other and further objects of the invention will be `apparent to those skilled in this art from the following detailed description of the annexed sheet of drawings which, by way of preferred example only illustrates one embodiment of the invention.

On the drawings:

FIGURE 1 is a somewhat diagrammatic transverse cross sectional view of -a twin drum dryer of the descending type embodying heating apparatus according to this invention.

FIGURE 2 is a view similar to FIG. 1 but illustrating a twin drum dryer of the ascending type including heating apparatus according to this invention.

FIGURE 3 is a longitudinal cross sectional view of a dryer drum of the twin drum dryers of FIGS. l and 2 taken generally along the line III-III of FIG. 2 and including parts in plan.

As shown on the drawings:

The twin drum dryer of FIG. 1 includes a pair of identical dryer drums 11, 11 in horizontal side-by-side relation and dening a nip area therebetween capable of carrying a pond P of material to be dried. The drums 11 rotate downwardly from the pond P to carry films of material from the pond around most of the periphery of the Idrums to scrapers 12 which remove the dried films F.

In the twin drum dryer 10a of FIG. 2 identical drums 11 are provided but .instead of receiving the-material Ito be dried from a top pond P they dip into a bottom pan or box 13 containing the pond P of material to be dried. The cylinders are rotated upwardly from this bottom pond P to carry films around the major portion of the peripheries thereof to scraper blades 14 positioned alongside of the pan 13 for removing the films F adjacent the bottoms of the drums.

Each drum 11 of FIGS. 1 and 2 is heated by internal heating apparatus 15 of this invention.

As better shown in FIG. 3 each drum 11 includes a metal cylindrical shell 16 and end heads 17 each provided with journals 18. Access plugs or manhole covers 19 `are provided in the end heads 1'7 to give ready access to the interior 20 of the drum.

The heating apparatus 15 includes a central steam pipe 21 extending through the journals 18 and across the entire interior 20 of the drum. Two perforated or slotted pipes 22 extend longitudinally along the entire length of the drum closely adjacent the shell 16 at the 3 and 9 oclock positions of the shell. The ends of these pipes 22 are connected to the central pipe 21 adjacent the end heads 17 by means of rigid mounting pipes 23 each of which contains a steam flow regulating valve 24. Suitable nipples 25 connect the pipes 23 fixedly with the central pipe at 21 while suitable T connectors 26 connect the outer ends of the pipes 23 with the pipes 22. These T connectors 26 receive not only the pipes 22 and 23 but also receive extension pipes 27 in their outer ends for carrying jet nozzles 28 to impinge jets on the end heads 17 of the drum. The pipes 22 are slotted or perforated along their length at 29 or if desired can carry jet nipples for ejecting steam jets 3l) against the shell 16 in a downward direction as shown in FIGS. 1 and 2.

Both ends of the central pipe 21 are connected to steam inlets 31 Eand 32 at the opposite ends of the drum. The central pipe 21 at the inlet end 31 is surrounded by a condensate pipe 33 also extending through the journal 18. The inner end of this pipe 33 is sealed to the pipe 21 at 34 and a syphon tube 35 depends from this inner end of the pipe 33 into the bottom of the drum to receive condensate water therefrom. A drain outlet 36 is connected to the pipe 33 at the outer end for removing the condensate water. Suitable packings (not shown) are provided in the journal 18 to accommodate rotation of the journal around the pipes 21 and 33 while at the same time sealing the interior of the drum.

Each steam inlet 31 and 32 includes a pressure regulating valve 37 which is adjustable at 38 to supply steam at a constant selected pressure to the opposite ends of the central pipe 21. A plug 39 is provided in the pipe 21 near the steam inlet 32 and a branch pipe 40 is provided immediately beyond the plug 39 to receive the steam from the inlet 32. This pipe d@ discharges through a nipple 41 positioned close to the pipe 21 and discharges into the central zone of the drum interior 2f) in a direction away from the end head 17.

The inlet 31 feeds steam along the length of the central pipe 21 up to the plug 39 and through the branch pipes 23 to the jet pipes 22 where steam is ejected against the drum shell as illustrated in FIGS. l and 2 and also against the drum end heads as illustrated in FIG. 3. rl`he regulating valves 37 are controlled to supply a higher steam pressure to the jet pipes 22 than to the nipple 41 and the valves 24 are regulated to distribute the steam as desired along the length of the tubes 22 for maintaining even heating of the shell. Thus if it develops that one end of the shell is being heated more than the other end, the valves 24 at the overheated end can be regulated to decrease the steam flow to this end thereupon increasing the ow to the opposite end.

As illustrated in FIGS. l and 2 the syphon tube 3S dips into a pool 42 of condensate Water from the jets and nipple. This pond 42 is maintained in the very bottom of each drum by the jets 30 which impinge against the shell 16 in a downward direction and drive any water which tends to rise along the shell interior back to the pond 42. The drums can be operated at very high speeds without developing a film of water around their interiors and the absence of this film increases the heat transfer of the steam through the shell 16 to the material to be dried on the shell. The apparatus therefore not only serves to concentrate the condensate'water in a small pool area 42 at the bottom of the drum but also keeps condensate water off of the shell interior above this pool eliminating any heat transfer loss to the shell.

It will of course be understood that the entire apparatus 15 remains stationary in the rotating drum l1 and that while the iet pipes 22 are shown as positioned at the 3 and 9 oclock zones of the drum they could be positioned either above or below the illustrated positions and if desired additional jet pipes 22 could be provided. For example seven jet pipes 22 could be used at the l2; 1:30; 3; 4:30; 7:30; 9', and 10:30 clockwise positions leaving the 6 oclock position for the condensate tube. In general any number of spoke pipes 23 could extend from the central pipe 21 to support and position jet pipes 22 as desired in the shell 16.

It will also be understood that the lm to be dried on the shells 16 can travel with the drums around most of the peripheries thereof and that only a small portion of this travel is backed by a pond of condensate water. In both the descending and ascending types of drum drier illustrated in FIGS. l and 2 the condensate water backs the material on the drum immediately after it is received on the drum.

Instead of positioning the condensate pipe 33 around the central pipe 21, it could go through one end of the pipe and if desired a petcock could be provided in one or both of the plugs 19 to check water level, etc.

The regulating valves 37 for the steam inlets 31 and 32 are easily manipulated and the steam pressures to the respective inlets are easily observed by the pressure gauges 43 tapped into the downstream ends of the valves. A desired pressure differential between the jet inlets 22 and nipple inlet 41 can be maintained. A large pressure differential will increase the impact effect of the jets on the shell but a proper diflerential can easily be maintained to provide elicient even heating around the drum peripheries.

While the heating system 15 has been described for use with steam it should be undertsood that other heating fluids such as Dowtherm, water, and the like can be used.

It will also be understood that while twin drum dryers are illustrated single as well as any multiple drum arrangements are included in this invention.

From the above descriptions it will be understood that the invention provides a heating system for drum dryers and the like which greatly increases the heat flow through the drum shell by maintaining a small condensate pool only at the bottom of the drum and by preventing condensate from building up as a iilm on the interior of the drum.

I claim as my invention:

1. In a dryer drum, a cylindricalshell, end heads closing the ends of the shell, journals on said end heads for rotatably supporting the drum, a pipe extending axially through the journals across the entire interior of the drum, a second pipe surrounding said first pipe in one of said journals, a syphon tube in the drum depending from the second pipe for removing spent heating fluid from the bottom of the drum, means for introducing heating iluid to both ends of the central pipe, a plugin the central pipe adjacent one end head, an outlet for the central pipe between the plug and the adjacent end head, a plurality of jet pipes extending longitudinally across the interior of the drum closely adjacent the shell, means for supplying heating fluid from the central pipe to the jet pipes and means for regulating heating iluid :flow to the outlet and jet pipes.

2. A drying drum which comprises a cylindrical shell, end heads closing the ends of the shell, .a central heating fluid inlet pipe extending axially through the shell and end heads, a plurality of jet equipped pipes in said shell extending along the length thereof in close proximity to the inner face of the shell, spoke pipes radiating from the central pipe connected to both ends of the jet equipped pipes to support the jet equipped pipes from the central pipe and to deliver heating iiuid to both ends of the jet pipes, means for feeding heating fluid into both ends of the central pipe, a plug in the central pipe dividing the pipe into two isolated passages, one of said passages communieating with all of said spoke pipes for distribution of heating iiuid to the jets of the jet equipped pipes for impinging directly against the inner face of the shell, and said central pipe having a direct outlet communicating with the other passage for feeding heating fluid into the central zone of the shell.

3. A drying apparatus which comprises a rotatable horizontal drum having a cylindrical shell, end heads closing the ends of the shell and journals projecting from the end heads for rotatably supporting the drum, stationary steam jet pipes in the drum having jet outlets along the length of the shell closely adjacent the interior surface thereof and at the ends thereof closely ladjacent the end heads, means for introducing steam through a journal into said jet pipes for ejection through the jet outlets directly against the shell and end heads, said outlets along the length of the shell being positioned to direct the steam in :a non-radial downward direction on the shell, a condensate outlet extending through a journal, a syphon tube in the drum joining the condensate outlet with the bottom of the drum, and means for controlling said means for introducing steam to maintain pressures in the jet pipes suiiiciently higher than the interior of the drum to impinge the steam jets against the shell and end heads with sucient force to destroy the condensate water films tending to build up on the shell and end heads and to drive the water to the bottom of the drum for removal through the syphon tube thereby increasing heat flow through the shell and confining the condensate to the bottom of the drum.

4. A drying apparatus comprising a rotatable horizontal duim having a shell to transfer heat from the interior to the exterior of the drum, end heads closing the ends of the shell and journals projecting from the end heads for rotatably supporting the drum, stationary jet pipes in the drum extending along the length of the shell in close proximity thereto, said jet pipes having steam outlets along the length thereof positioned to direct steam jets only in a non-radial downward direction against the shell, said jet pipes also havin-g steam outlets at the ends thereof to direct steam jets against said end heads, means for introducing steam through a journal into said jet pipes for ejection therefrom through the steam outlets, a condensate outlet extending through a journal, a syphon tube in the drum joining the condensate outlet with the bottom of the drum, and means controlling said means for feeding steam to the jet pipes for maintaining steam in the jet pipes at a pressure sufficiently higher than the pressure of the drum interior for ejecting the steam jets with su'cient force to impinge on the shell and destroy condensate `water lm thereon and to drive the condensate Water to the drum bottom for removal lby said syphon tube.

5. The drying .apparatus of claim 3 wherein the jet pipes extend longitudinally across the shell at the 3 and 9 oclock positions thereof.

6. A dryer drum which comprises a cylindrical shell, end heads closing the ends of the shell, a central heating uid inlet pipe extending axially through the shell and end heads, a plurality of jet pipes in said shell extending along the length thereof in close proximity to the inner face of the shell, spoke pipes radiating from the central pipe connected to both ends of the jet pipes for supporting the jet pipes from the central pipe, a plug in the central pipe dividing the pipe `into two isolated passages, one of said passages communicating with all of said spoke pipes, means for feeding steam to the ycentral pipe for ow through said one passage through the spoke pipes to the ends of the jet pipes for ejection through the jet outlets of the jet pipes directly against the inner face of the shell, means connecting the other passage of the central pipe with the exterior of the drum, a syphon pipe communicating with the bottom of the, drum for `removing condensate water therefrom, and means maintaining steam pressure in the jet pipes higher than the pressure of the interior of the drum for impacting the steam jets against the shell with sutlicient velocity to destroy condensate lm on the shell, and said jet pipes positioning said jet outlets to direot the steam jets in a non-radial downward direction on the shell to the bottom of the drum for removal of condensate water through said syphon pipe.

References Cited by the Examiner UNITED STATES PATENTS 1,189,761 7/1916 White 34-124 1,768,777 7/1930 Moller 34-124 2,034,599 3/ 1936 Van Marle.

2,677,898 5/1954 Ohlson 34-124 2,837,833 6/1958 Coudriet 34-124 2,879,039 3/1959 Skinner 34-124 2,915,293 12/1959 Justus et al. 34-124 KENNETH W. SPRAGUE, Primary Examiner. 

1. IN A DRYER DRUM, A CYLINDRICAL SHELL, END HEADS CLOSING THE ENDS OF THE SHELL, JOURNALS ON SAID END HEADS FOR ROTATABLY SUPPORTING THE DRUM, A PIPE EXTENDING AXIALLY THROUGH THE JOURNALS ACROSS THE ENTIRE INTERIOR OF THE DRUM, A SECOND PIPE SURROUNDING SAID FIRST PIPE IN ONE OF SAID JOURNALS, A SYPHON TUBE IN THE DRUM DEPENDING FROM THE SECOND PIPE FOR REMOVING SPENT HEATING FLUID FROM THE BOTTOM OF THE DRUM, MEANS FOR INTRODUCING HEATING FLUID TO BOTH ENDS OF THE CENTRAL PIPE, A PLUG IN THE CENTRAL PIPE ADJACENT ONE END HEAD, AN OUTLET FOR THE CENTRAL PIPE BETWEEN THE PLUG AND THE ADJACENT END HEAD, A PLURALITY OF JET PIPES EXTENDING LONGITUDINALLY ACROSS THE INTERIOR OF THE DRUM CLOSELY ADJACENT THE SHELL, MEANS FOR SUPPLYING HEATING FLUID FROM THE CENTRAL PIPE TO THE JET PIPES AND MEANS FOR REGULATING HEATING FLUID FLOW TO THE OUTLET AND JET PIPES. 